Embodiments in accordance with the present invention relate generally to techniques including methods and a structure for forming substrates, including for example doped substrates, using a large scale implantation process. More particularly, embodiments of the present method and system provides a method and system using a scanning implant process for the manufacture of photovoltaic cells. But it will be recognized that the invention has a wider range of applicability; it can also be applied to other types of applications such as for three-dimensional packaging of integrated semiconductor devices, photonic devices, piezoelectronic devices, flat panel displays, microelectromechanical systems (“MEMS”), nano-technology structures, sensors, actuators, integrated circuits, biological and biomedical devices, and the like.
From the beginning of time, human beings have relied upon the “sun” to derive almost all useful forms of energy. Such energy comes from petroleum, radiant, wood, and various forms of thermal energy. As merely an example, human being have relied heavily upon petroleum sources such as coal and gas for much of their needs. Unfortunately, such petroleum sources have become depleted and have lead to other problems. As a replacement, in part, solar energy has been proposed to reduce our reliance on petroleum sources. As merely an example, solar energy can be derived from “solar cells” commonly made of silicon.
The silicon solar cell generates electrical power when exposed to solar radiation from the sun. The radiation interacts with atoms of the silicon and forms electrons and holes that migrate to p-doped and n-doped regions in the silicon body and create voltage differentials and an electric current between the doped regions. Depending upon the application, solar cells have been integrated with concentrating elements to improve efficiency. As an example, solar radiation accumulates and focuses using concentrating elements that direct such radiation to one or more portions of active photovoltaic materials. Although effective, these solar cells still have many limitations.
As merely an example, solar cells rely upon starting materials such as silicon. Such silicon is often made using either polysilicon and/or single crystal silicon materials. These polysilicon or single crystal silicon materials may be doped with impurities to form light absorbing regions.
These materials are often difficult to manufacture as implantation processes may be inefficient and not optimal for such application. Polysilicon cells are often formed by manufacturing polysilicon plates. Although these plates may be formed effectively, they do not possess optimum properties for highly effective solar cells.
Single crystal silicon has suitable properties for high grade solar cells. Such single crystal silicon is, however, expensive and is also difficult to use for solar applications in an efficient and cost effective manner. Generally, thin-film solar cells are less expensive by using less silicon material but their amorphous or polycrystalline structure are less efficient than the more expensive bulk silicon cells made from single-crystal silicon substrates.
These and other limitations can be found throughout the present specification and more particularly below.